New guy with overheat issue

[CharlieL]

Hey Guys, first off, thanks for having me on the forum. I am the 3rd owner of a 1991 Ski Supreme down here in Texas. I've been looking around and couldn't find my answer so I'm forced to make a newbie move and ask something thats been asked before im sure. As stated I have a 1991 Ski supreme direct drive, I've owned it for 2 summers now. After the 1st summer I had the interior redone and the boat tuned up before it sat up for winter. Texas winters don't get very cold so not much to do. Well, I took it out the beginning of summer and it ran much better than last summer but now I have an overheating issue. Temp will get up to 240 and when I open the engine cover it will go back down to 165 ish. I had no issues last summer. So far I've noticed the blower was blowing air into the engine cover and ive fixed that. And idled up the engine about 200 ram, seems to like that better also. In the winter I had8n a new fresh water pump put on it since the old impeller was about done. For the life of me I can't think what it could be. Thinking of changing the thermostat next since thats all I have left in my mind that it could be. Any suggestions would be greatly appreciated.

Thanks for letting me be a part of the forum.

[charlesml3]

I can't think of any way opening the cover would make any difference. These are not air-cooled engines.

Meticulously go through the cooling system. Strainer, impeller, thermostat, transmission cooler. Make sure you don't have an air leak somewhere.

-Charles

[CharlieL]

Will do. Thanks for the reply

[CharlieL]

I'm thinking it going to need a thermostat.
Anyone know where to get windshields and parts from?? Need some quarter windows and some frame parts

[Jonny Quest]

Get an infra-red temperature gun and go boating. Shoot temps at the thermostat housing and water inlet of the intake manifold. This can help you diagnose the situation. To start with I would replace the thermostat and gasket. Impeller inspection and replacement is not a bad idea. Your hose clamps need to be tight. Use a nut driver and not just a screw driver to tighten. An air leak will impact temps. Look At hose condition and clamps before and after the raw water pump.

JQ

[CharlieL]

I think I fixed it. I replaced the waterpump and the thermostat. Neither looked like they had ever been changed. Ran the boat in the driveway with the cover closed for about 45 minutes with the fake a lake hooked up while I was cleaning the outside. Never got over 160*. Heading to the lake as I'm typing to give it a good test. I will report back. I had to beat the old thermostat out of the housing when I took it apart. Should have been a clue to me i guess. Don't think it was maintained well before I picked it up from the second owner.

[CharlieL]

It's Fixed!! Never went over 165* the entire weekend. Thanks for the tips guys. Now I need to get a windshield and a fitted cover. Any recommendations?

[charlesml3]

So to clarify, did you replace the entire raw water pump, the raw water pump impeller, or the circulation pump?

-Charles

[CharlieL]

raw water pump was replaced last winter. Circulation pump and thermostat. They looked like they had never been replaced. But didn't look too bad since its only ever been in freshwater